Transcript Poaceae The Grass Family

Poaceae
The Grass Family
Alex Stalboerger
Poaceae
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900 Genera
9,000 – 10,000 species of “true grasses”
Monocot, flowering plants
Comprise 20% of vegetation on Earth
Considered the most important family in
respect to Human economy, used for
agriculture, lawn foliage, forage grasses, etc.
Poaceae Characteristics
• Grasses have hollow stems called culms,
which are plugged in intervals called nodes.
• Leaves are alternate, distichous (one-planed),
rarely spiral, and are parallel-veined.
• Each leaf is differentiated into a lower sheath
which hugs the stem for a distance
• Blades usually have entire margins
http://en.wikipedia.org/wiki/File:Grass-plant-structure.png
Poaceae Characteristics
• Flowers of Poaceae are arranged in spikelets,
each having one or more florets.
• Spikelet consists of two, or fewer, bracts at the
base, called glumes, followed by one or more
florets.
• Parianth reduced to two scales, called
lodicules, that expand and contract to spread
the lemma and palea (interpreted both as
modified sepals)
http://en.wikipedia.org/wiki/File:En_Anatomia.png
Poaceae Growth
• Three general classifications of growth habit
present in grasses: bunch types (caespitose),
stoloniferous, and rhizomatous.
• Two physiological groups C3 and C4
– Determined by metabolic pathway of
photosynthetic efficiency
– C3 ex. Wheat, Rye, Oat
– C4 ex. Corn, Pearl millet, Big Bluestem
Andropogon gerardii – Big Bluestem
• Perennial
• 4-8ft tall
• Seedhead usually
branched into
three parts and
resembles a
turkey’s foot.
http://www.google.com/imgres?imgurl=http://www.sbs.utexas.edu/bio406d/images/pics/po
a/Andropogon%2520gerardii%2520infl1.jpg&imgrefurl=http://www.sbs.utexas.edu/bio406d/i
mages/pics/poa/andropogon_gerardii.htm&usg=__IwsLgW1DTHrztOs0ykdMAxUOu84=&h=42
9&w=640&sz=35&hl=en&start=1&itbs=1&tbnid=o5N3hkn7IWm9hM:&tbnh=92&tbnw=137&p
rev=/images%3Fq%3Dandropogon%2Bgerardii%26hl%3Den%26gbv%3D2%26tbs%3Disch:1
Brachyelytrum erectum – Bearded
shorthusk
• Perennial
• 1-2ft tall
• Upper leaf surface is
hairless but lower
margin is slightly
hairy
http://www.missouriplants.com/Grasses/Brachyelytrum_erectum_pag
e.html
Calamagrostis canadensis - Bluejoint
• Perennial
• 3-5ft tall
• Many slender stems
arise from small
rhizomes
• Each topped with
large, slightly
nodding, branched
inflorescence.
http://www.google.com/imgres?imgurl=http://botit.botany.wisc.edu/images/veg/W
et_Prairie/Calamagrostis_canadensis_VK.jpg&imgrefurl=http://botit.botany.wisc.edu
/images/veg/Wet_Prairie/Calamagrostis_canadensis_VK.php%3Fhighres%3Dtrue&h=
482&w=715&sz=105&tbnid=HHc8EFi2qUXQlM:&tbnh=94&tbnw=140&prev=/images
%3Fq%3Dcalamagrostis%2Bcanadensis&hl=en&usg=__gTfWUxxQd6LGfnGkvJtGpGCj
dYQ=&ei=KKvVS8TmHoSCNuPd9dID&sa=X&oi=image_result&resnum=1&ct=image&v
ed=0CA0Q9QEwAA
Danthonia spicata – Poverty grass
• Perennial
• 1-1.5ft tall
• Blades 5” long,
often curving left or
right
• Small tuft of hairs at
apex of sheath
http://www.google.com/imgres?imgurl=http://www.mbrpwrc.usgs.gov/herbarium/danthonia_spicata.jpg&imgrefurl=http://www.mbrpwrc.usgs.gov/herbarium/danthonia_spicata.htm&h=384&w=560&sz=44&tbnid=WRPpEteB7eaLZM
:&tbnh=91&tbnw=133&prev=/images%3Fq%3Ddanthonia%2Bspicata&hl=en&usg=__rRFvq2zFPBm1
nlcGRJs4M1jqoLs=&ei=5qvVS_TCCJWINM_r6NcG&sa=X&oi=image_result&resnum=4&ct=image&ve
d=0CA4Q9QEwAw
Elymus virginicus – Virginia wild rye
• Perennial
• 2.5-4ft tall
• Each leaf is 2/3” wide
and 1ft long, shortly
pubescent
• Floral spikes are 2-6”
tall and erect
http://www.missouriplants.com/Grasses/Elymus_virginic
us_inflorescence.jpg
Glyceria striata – Fowl manna grass
• Perennial
• 2-3.5ft tall
• 6 alternate leaves
along its length
• Tendency to drupe
downwards
http://www.illinoiswildflowers.info/grasses/plants/fm_gr
ass.htm
Oryzopsis asperifolia – Mountain rice grass
• Perennial
• 20-70cm tall
• Most leaves at stem
base, 3-10mm wide,
tape at both ends
• Hairy fringes at ends
• Simple, few-flowered,
spike-like panicle
http://www.agf.gov.bc.ca/range/RangeID/Images/oryz
opsis%20asperifolia1.jpg
Schizachne purpurascens – False melic grass
• Perennial
• 40-80cm tall
• Leaves 1-6mm wide,
narrow at base,
sheaths closed at
first but split at
maturity
• Drupes at stem
inflorescens
http://upload.wikimedia.org/wikipedia/commons/e/e7/Schizachne_p
urpurascens_flowers_001.JPG
Sources
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http://en.wikipedia.org/wiki/Poaceae
www.borealforest.org
plants.usda.gov
All images cited at base